10 a.m.-4 p.m. Celebrate Germantown’s rich history at Revolutionary Germantown Festival, a one day event on the Cliveden grounds, with programs, tours and activities throughout the community, at the many historic sites. The festival is highlighted by the annual reenactment of the Battle of Germantown, which commemorates the October 4, 1777 battle, when the Continental Army attempted to fight the British out of Germantown. Washington and his troops lost the battle and were forced to retreat to Valley Forge for the winter.